High-temperature wear behaviour of laser-textured assisted cold-sprayed metal matrix composite coatings: tamping effect of particles in a confined space

To address the surface protection challenges faced by turbine blades in gas turbines under extreme operating conditions—including high temperatures, high pressures, and high-velocity gas combustion gases—this study employs an efficient composite process combining laser surface texturing with cold spraying (LST-CS). This process is designed to enhance the interfacial bonding of cold-sprayed nickel-based coatings, thereby improving their operational reliability and extending component lifespan. Following substrate pretreatment, coating porosity decreased by 2.28%, bond strength increased by 3.68-fold, and wear rates at ambient and elevated temperatures decreased by 52.67% and 68.71% respectively. Experimental and characterisation analyses revealed that the textured groove structures not only increased particle-substrate contact area but also functioned as a guiding framework directing particle deposition. This induced a ceramic tamping effect within confined spaces, establishing a mortise-and-tenon mechanical interlocking structure at the coating-substrate interface. This structure not only enhances the bonding strength between the coating and the substrate, promoting overall densification of the coating, but also effectively suppresses crack initiation at elevated temperatures through dovetail mechanical anchoring. By leveraging substrate softening, it transforms frictional loads into lateral compression that reinforces interfacial bonding, thereby significantly mitigating high-temperature shear slippage and interfacial delamination. This extends the service life of the coating and provides a theoretical foundation and technical guidance for improving the surface repair performance of high-end equipment under extreme operating conditions.